Intervention Report Scheduling out-of-merit-order injections at Iona CPP to avert a threat to system security during Brooklyn Compressor Outage

Transcription

1 INTRODUCTION Interventin Reprt Scheduling ut-f-merit-rder injectins at Ina CPP t avert a threat t system security during Brklyn Cmpressr Outage Intrductin AEMO declared a threat t system security in the Victrian Declared Whlesale Gas Market (DWGM) fr gas days between 18 April and 2 May 2016 during a planned utage f the Brklyn Cmpressr Statin. Clause 351(1)(b) f the Natinal Gas Rules (Part 19) requires that AEMO investigate and prepare a reprt fllwing declaratin f a threat t system security. Clause 351 als requires that AEMO assess and advise n: the adequacy f the prvisins f the Rules relevant t the event r events; the apprpriateness f actins taken by AEMO in relatin t the event r events; and the csts incurred by AEMO and Registered participants as a cnsequence f respnding t the event r events. This reprt addresses each f these requirements. Backgrund In December 2014, APA GasNet advised that it wuld cmmence planning fr a full utage f the Brklyn Cmpressr Statin (BCS) t replace the statin islatin valves t meet safety requirements. The BCS is primarily used t: supprt gas exprts int Ina undergrund gas strage at Prt Campbell (Ina UGS); assist in balancing system linepack fr efficient peratins; supprt system demand in the Brklyn t Lara Pipeline (BLP), Suth West Pipeline (SWP) and the Western Transmissin System (WTS); supprt gas pwered generatin at Lavertn; and maintain pressures abve perating limits in the Brklyn-Cri Pipeline and the Brklyn- Ballan Pipeline n high demand days. When the BCS is unavailable, net injectins at the Ina clse prximity pints (Ina CPP) are required t meet demand that is supplied frm the BLP, SWP and WTS. AEMO and APA GasNet cnsidered a number f pssible utage alternatives during a series f maintenance crdinatin meetings in It was decided that cmpleting this maintenance during a single utage perid in April wuld result in the least disruptin t DTS peratin 1. On 6 April 2016, AEMO issued a market ntice advising participants f: a full utage f the Brklyn Cmpressr Statin t replace statin islatin valves t meet safety requirements starting 18 April, with a planned cmpletin date f 30 April 2016; the net injectin requirements at the Ina CPP fr supplying demand n the BLP, SWP and WTS, including a scheduling prcess whereby AEMO wuld: 1 The cnsideratin includes the impact n supprting the gas pwered generatin, refilling f the Ina Undergrund Gas Strage facility and maintaining minimum pressures at key pints within the DTS fr high demand days. 6 May 2016 Page 1 f 5

2 SCHEDULING OUTCOME allw cntrllable withdrawal bids t be scheduled n the cnditin that there are sufficient physical injectins at the Ina CPP t supprt the withdrawals and system demand n the BLP, SWP and WTS; and restrict cntrllable withdrawal bids t be scheduled prir t calling n ut-f-merit-rder injectins t avert the threat t system security, if insufficient net injectins are likely t be scheduled; and ntice that AEMO will declare a threat t system security, and schedule ut-f-merit-rder injectins at the Ina CPP, if pressures n the BLP, SWP and WTS are frecast t fall belw minimum perating limits. On 11 April 2016, AEMO prvided an verview f the utage t participants at the Gas Whlesale Cnsultative Frum meeting. On 13 April 2016, AEMO held an industry cnference t infrm participants f the: scpe f BCS wrk and peratinal impact n the DTS; DWGM scheduling prcess t be applied during this utage; and market ntices that AEMO will issue, and the intent f these ntices. On 15 April 2016, AEMO issued a market ntice seeking a market respnse t the threat t system security fr the utage perid frm 18 t the 30 April. AEMO als sent ntices seeking a market respnse, t advise n the threat, quantificatin f ut-f-merit rder injectins, and t advise when the threat had subsided. The utage was extended fr an additinal tw days until 2 May BCS resumed nrmal peratins frm 6:00AM the 3 May Scheduling utcme The impact n scheduling utcmes is separated int three sectins belw: lst pprtunity t withdraw gas at Ina CPP int the Ina UGS facility; scheduling f ut-f-merit-rder injectins (abve market price bids); and increased ancillary payments and uplift payments as a result f the scheduling ut-f-meritrder injectins. Lst pprtunity t withdraw gas at Ina CPP T schedule the required net injectins at Ina CPP during the Brklyn Cmpressr Statin utage, AEMO de-scheduled a ttal f 208 TJ f cntrllable withdrawals in the 6AM perating schedules during the perid. This de-scheduling f withdrawals ccurred despite sme market respnse during the BCS utage. It is likely that the de-scheduled withdrawal quantity wuld have been much higher in the absence f a market respnse. Fr example, the expected daily cntrllable withdrawal during the 15 day utage was apprximately 100 TJ/d r a ttal f 1,500 TJ. The table belw lists the de-scheduled withdrawal quantities (in GJ) at the Ina CPP in the perating schedules fr the gas days 18 April t 2 May Apr-16 28,750 2,873 14,682 13,561 34, Apr-16 66,250 50,330 46,497 46,443 1, Apr-16 21,456 17,330 12,330 29,580 16, Apr-16 22,150 37,416 12,330 11,844 11, Apr-16 1,250 12,330 12,330 12,239 15, Apr-16 1,250 1,497 6,434 1,974 9,734 6 May 2016 Page 2 f 5

3 MARKET IMPACT 24-Apr-16 1, ,127 14,705 18, Apr-16 9,782 13,646 13,281 16,790 16, Apr-16 1,250 1,080 1,080 6, Apr-16 8,750 8,580 11,080 11,080 10, Apr-16 1,250 7,237 4,382 6, Apr-16 1,250 2,080 5,197 3, Apr-16 1,250 1, May-16 26,250 26,080 25,864 25,648 15, May-16 16,250 16, The changes in the withdrawal quantities between scheduling hrizns were mainly due t intra-day re-bidding, which resulted in changes t the market price and therefre cntrllable withdrawal quantities in the pricing schedules. Out-f-merit-rder injectin In respnse t the threats t system security, AEMO scheduled the minimum required net injectin at the Ina CPP, which included sme ut-f-merit-rder injectins (abve market price bids). During the 15 day utage, AEMO scheduled a ttal f 223 TJ f ut-f-merit-rder injectins in the 6AM perating schedules. The table belw lists the ut-f-merit-rder injectins (in GJ) at the Ina CPP in the perating schedules fr each gas day frm 18 April t 2 May Apr-16 13, Apr-16 12,497 7,399 3,919 2, Apr-16 12,572 1, ,292 1, Apr-16 14,472 1,464 1,191 1, Apr-16 23,172 8,582 6,865 5,149 3, Apr-16 21,497 6,000 4,800 3,600 2, Apr , Apr-16 15,497 2,914 2, Apr-16 16,797 13, Apr-16 16,597 1,331 1, Apr-16 16,197 9,332 7,465 5,598 3, Apr-16 16,797 18,999 14,827 10,220 5, Apr-16 9,997 8,331 6,665 2,749 1, May-16 20,197 16,832 13,465 10,099 6, May-16 13, , The changes in the ut-f-merit-rder injectin quantities between scheduling hrizns were mainly due t intra-day re-bidding, which resulted in changes t the merit rder bid stacks. Market impact The market impact resulting frm the threats t system security are in the frm f additinal Ancillary Payments (AP) and crrespnding Uplift Payments (UP). The table belw lists these payments by type fr each gas day frm 18 April t 2 May May 2016 Page 3 f 5

4 ADEQUACY OF THE NGR Ancillary Payments Cngestin Uplift Surprise Uplift Cmmn Uplift Gas Day ($) 18-Apr-16 2,956 2, Apr-16-18,357-2,138-16,219 2, Apr-16 32,996 20,291 9,102 3, Apr-16 42,796 41, Apr-16 27,270 24,474 2, Apr-16 21,892 19, Apr Apr-16 25,700 2,914 2, Apr-16 20,804 15, Apr-16 15,810 12, Apr-16 5,640 4,551 1, Apr-16 35,127 25,235 9, Apr-16 12,705 9,876 2, May-16 4,544 4, May-16 1,346 1, The key results can be summarised as fllws: The ttal APs assciated with the ut-f-merit rder injectins at Ina CPP during the perid 18 April t 2 May 2016 are apprximately $231,000. The nn-psitive AP values seen n gas days 19 April 2 and 24 April 2016 were primarily due t sme participants nminating their scheduled injectins as an uplift hedge, which rendered their ut-f-merit-rder scheduled injectins ineligible fr ancillary payments. Uplift payments were categrised as apprximately 88% cngestin uplift, 11% surprise uplift, and 1% cmmn uplift. Cngestin uplift is allcated t participants when their daily prfiled demand frecasts and scheduled cntrllable withdrawals exceed their AMIQ (prfiled uplift hedge). Surprise uplift is allcated t participants wh were deemed t have wrsened the cnstraint at reschedules. Fr example, when participants under-inject r verwithdraw in the preceding schedule (fr psitive APs). Cmmn uplift is any remaining uplift that cannt be allcated as cngestin r surprise uplift, and is applied acrss participants in prprtin t their actual withdrawal quantities ver a gas day. Adequacy f the NGR In respect f this event, AEMO has assessed the applicatin and adequacy f NGR prvisins relating t maintenance apprval, market ntices, and this interventin reprt. Maintenance apprval NGR 326(1) requires that AEMO crdinate maintenaince t ensure that system security is nt threatened, while NGR 326(4) requires AEMO and service prviders t cperate t minimise any threat t system security. 2 Please refer t the GWCF paper Impact f Negative APs n settlement utcme fr further explanatin f negative APs 6 May 2016 Page 4 f 5

5 CONCLUSIONS In this case, AEMO determined that cmpleting this maintenance, wuld result in a ptential threat t system security which culd nt be reslved thrugh crdinatin. In additin, the prpsed maintenance apprach wuld minimise the threat cmpared with ther maintenance ptins, r deferring maintenance (given that the existing statin islatin valves failed t meet critical safety requirements). AEMO finds that these NGR prvisins were applied crrectly in this case, thugh NGR 326(1) culd be better clarified t acknwledge that crdinatin may nt be sufficient t remve all threats t system security assciated with planned maintenance activities. Market ntice NGR 342 requires that when AEMO identifies a ptential threat t system security, it must ntify Registered participants as sn as practicable including details f the nature and lcatin f ptential threat, and AEMO's estimate n whether interventin will be required. In this case, AEMO issued a market ntice n 6 April 2016 advising Registered participants f the planned BCS utage between 18 and 30 May, and its impact n DWGM peratins. An industry cnference was held n 13 April t explain the scpe f maintenance, prpsed AEMO scheduling prcess, and market ntificatin prtcl. On 15 April 2016, AEMO issued a market ntice seeking market respnse t the threat t system security fr the utage perid frm 18 t the 30 April. In this case, after seeking a market respnse, and assessing the respnse prvided, AEMO determined that it was necessary t schedule net injectins at Ina CPP t balance system demand by bth restricting cntrllable withdrawals, and calling n ut-f-merit-rder injectins. AEMO subsequently issued a series f ntices seeking market respnses when the ut-f-meritrder injectins were frecast fr Ina CPP, when such injectins were used due t the declared threat n the current gas day, and when the threat had subsided after publicatin f the 10PM perating schedule each day. AEMO finds that these NGR prvisins are adequate, and were applied crrectly in this case. Interventin reprt NGR 351 requires that AEMO must investigate and prepare a reprt n the circumstances and impact f a declared threat t system security and subsequent interventin. This reprt must be prepared within 10 business days after the event cncludes. AEMO finds that these NGR prvisins were applied crrectly in this case, hwever believes that a 20 business day timeframe wuld be mre apprpriate t ensure adequate analysis particularly fr mre cmplicated market scenaris r significant events. Cnclusins AEMO declared a threat t system security in the Victrian DWGM fr the gas days starting 18 April thrugh t 2 May 2016 during a planned utage f the Brklyn Cmpressr Statin. In particular, ver the 15 day utage perid, AEMO de-scheduled 208 TJ f cntrllable withdrawals and scheduled a ttal f 223 TJ f ut-f-merit-rder injectins in the 6AM schedules. This resulted in apprximately $231,000 f additinal ancillary and uplift payments. This uplift was categrised as apprximately 88% cngestin uplift, 11% surprise uplift, and 1% cmmn uplift. Fllwing this event, AEMO has assessed the applicatin and adequacy f assciated NGR prvisins, and finds that these prvisins were applied crrectly. 6 May 2016 Page 5 f 5